首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4853篇
  免费   299篇
  国内免费   29篇
耳鼻咽喉   75篇
儿科学   112篇
妇产科学   150篇
基础医学   634篇
口腔科学   212篇
临床医学   471篇
内科学   907篇
皮肤病学   162篇
神经病学   208篇
特种医学   144篇
外科学   840篇
综合类   79篇
一般理论   3篇
预防医学   339篇
眼科学   84篇
药学   483篇
中国医学   37篇
肿瘤学   241篇
  2024年   5篇
  2023年   48篇
  2022年   145篇
  2021年   200篇
  2020年   132篇
  2019年   184篇
  2018年   227篇
  2017年   174篇
  2016年   179篇
  2015年   194篇
  2014年   273篇
  2013年   317篇
  2012年   439篇
  2011年   436篇
  2010年   251篇
  2009年   194篇
  2008年   270篇
  2007年   232篇
  2006年   211篇
  2005年   188篇
  2004年   149篇
  2003年   129篇
  2002年   113篇
  2001年   36篇
  2000年   42篇
  1999年   38篇
  1998年   23篇
  1997年   22篇
  1996年   26篇
  1995年   20篇
  1994年   14篇
  1993年   18篇
  1992年   18篇
  1991年   22篇
  1990年   24篇
  1989年   18篇
  1988年   14篇
  1987年   26篇
  1986年   24篇
  1985年   13篇
  1984年   8篇
  1983年   10篇
  1982年   9篇
  1981年   8篇
  1980年   11篇
  1979年   5篇
  1978年   5篇
  1971年   8篇
  1970年   4篇
  1966年   4篇
排序方式: 共有5181条查询结果,搜索用时 11 毫秒
91.
92.
Criteria for the diagnosis of serrated colorectal lesions (hyperplastic polyp, sessile serrated adenoma without or with dysplasia—which we called mixed polyp—and traditional serrated adenoma) for which consensus has been reached should be validated for applicability in daily practice in terms of inter-observer reproducibility and their association with clinical features and (epi)genetic events. A study set was created from a consecutive series of colorectal polyps (n?=?1,926) by selecting all sessile serrated adenomas, traditional serrated adenomas and mixed polyps. We added consecutive series of hyperplastic polyps, classical adenomas and normal mucosa samples for a total of 200 specimens. With this series, we conducted an inter-observer study, encompassing ten pathologists with gastrointestinal pathology experience from five European countries, in three rounds in which all cases were microscopically evaluated. An assessment of single morphological criteria was included, and these were correlated with clinical parameters and the mutation status of KRAS, BRAF and PIK3CA and the methylation status of MLH1. Gender, age and localisation were significantly associated with certain types of lesions. Kappa statistics revealed moderate to good inter-observer agreement for polyp classification (κ = 0.56 to 0.63), but for single criteria, this varied considerably (κ = 0.06 to 0.82). BRAF mutations were frequently found in hyperplastic polyps (86 %, 62/72) and sessile serrated adenomas (80 %, 41/51). KRAS mutations occurred more frequently in traditional serrated adenomas (78 %, 7/9) and less so in classical adenomas (20 %, 10/51). Single morphological criteria for sessile serrated adenomas showed significant correlation with BRAF mutation (all p?≤?0.001), and those for classical adenomas or traditional serrated adenoma correlated significantly with KRAS mutation (all p?<?0.001). Therefore, single well-defined morphological criteria are predictive for genetic alterations in colorectal polyps.  相似文献   
93.
Periodontitis may exert an infectious and inflammatory burden, evidenced by increased C-reactive protein (CRP). This burden may impair blood glucose control (HbA1c). The aim of our study was to analyze whether periodontitis severity as measured with the periodontal inflamed surface area (PISA) and CRP predict HbA1c levels in a group of healthy Indonesians and a group of Indonesians treated for type 2 diabetes mellitus (DM2). A full-mouth periodontal examination, including probing pocket depth, gingival recession, clinical attachment loss, plaque index and bleeding on probing, was performed in 132 healthy Indonesians and 101 Indonesians treated for DM2. Using these data, PISA was calculated. In addition, HbA1c and CRP were analyzed. A validated questionnaire was used to assess smoking, body mass index (BMI), education and medical conditions. In regression analyses, it was assessed whether periodontitis severity and CRP predict HbA1c, controlling for confounding and effect modification (i.e., age, sex, BMI, pack years, and education). In healthy Indonesians, PISA and CRP predicted HbA1c as did age, sex, and smoking. In Indonesians treated for DM2, PISA did not predict HbA1c. Periodontitis may impair blood glucose regulation in healthy Indonesians in conjunction with elevated CRP levels. The potential effect of periodontitis on glucose control in DM2 patients may be masked by DM2 treatment. Clinical relevance: periodontitis may impair blood glucose control through exerting an inflammatory and infectious burden evidenced by increased levels of CRP.  相似文献   
94.
95.
Gastrointestinal stromal tumour (GIST) is the most common mesenchymal neoplasm of the GI tract. GISTs form a biological continuum ranging from benign incidentally detected minute lesions (stromal tumourlets) of no clinical significance to large and highly malignant sarcomatous neoplasms. The disease is characterized by indistinct borders between biologically different subsets within its spectrum leading to unpredictable course of the disease in the majority of cases. Availability of effective tyrosine kinase inhibitors underlined the urgent need for a reliable risk assessment system to reliably identify those patients who are at a significant risk for disease relapse and would thus profit from currently available effective targeted molecular therapy. While several risk systems have been established for GIST over the last decade, evidence is growing that no single system is optimal for all patients. Accordingly, an individualized risk system integrating classical parameters (site, size, mitotic index), status of serosal mechanical barrier covering the tumour (presence of tumour rupture or serosal penetration) as well as several other still debatable histological (coagulative necrosis, venous invasion, mucosal infiltration), biomarkers (proliferative index, p16 expression, etc.), and molecular (specific mutation types, adverse chromosomal aberrations, etc.) prognosticators would be of superb value for selecting the most appropriate patient treatment.  相似文献   
96.
Background: Hibernoma is a rare benign fat-forming soft tissue tumor that differentiates similar to brown fat, hence an origin from remnants of fetal brown adipose tissue has been proposed. Mainly young adults are affected, usually without significant clinical symptoms. Material and methods: We report on four patients with hibernomas, who were treated at our hospital during the last 10 years. The clinicopathologic and immunohistochemical features are presented and treatment and follow-up data discussed. Results: Patients were 2 women and 2 men aged 21-67 years (mean: 45 yrs) who presented with a slowly growing, painless mass. The anatomic location was the thigh, upper arm, lateral thoracic wall and paravertebral soft tissue. Two of them were diagnosed preoperatively through a percutaneous core needle biopsy and the other two underwent surgery because of high clinical and radiological suspicion of liposarcoma. The tumor’s size ranged from 7 cm to 15.5 cm (mean: 11 cm). All were deep-seated subfascial intramuscular masses. Histologically, all four tumors were of the typical variant. All patients underwent a R0-surgical resection of the tumor and they were recurrence-free at last follow-up (mean: 47 months; range: 25-87). Conclusion: Hibernoma may present as huge deep intramuscular soft tissue mass in adults, closely mimicking well differentiated liposarcoma and should be considered in the differential diagnosis of fatty soft tissue tumors in any location. Surgical excision is the treatment of choice. The tumor has no malignant or recurrence potential.  相似文献   
97.
Fumonisin B1 is a common secondary metabolite produced by Fusarium moniliforme that occurs in corn and corn-based foods. This mycotoxin is toxic to many species of laboratory and domestic animals and is known to induce a variety of diseases such as hepatic cancer and renal and hepatic dysfunction. The structure of fumonisin B1 (FB1) resembles sphingolipids so it can inhibit synthesis of ceramide, an enzyme in the sphingolipid biosynthetic pathway. This inhibition leads to the disruption of sphingolipid metabolism and increased levels of sphinganine and sphingosine (sphingoid bases) in the serum of treated animals. It is believed that the toxicity effect of fumonisin B1 is the result of these sphingoid bases. In the present research, mice were treated with FB1 to determine its pathological effects on gastric gland and gastric mucosa in the treated mice. For this purpose, the mice were randomly assigned into two groups, namely, control (n?=?14) and treatment (n?=?15). The treatment group was fed with prepared food containing FB1 (150 mg/kg) for a period of 4 months. One day after the last treatment, all animals in both groups were euthanized and their stomach were sampled and prepared for microscopic analysis. Histopathological analysis revealed a significant decrease in parietal cell number and a significant increase in the number of inflammatory cells in gastric mucosa. Also, atrophy of gastric glands was observed. The study confirmed that FB1 poisoning can have toxicopathological effects such as gastric gland atrophy and gastritis on mice gastric tissue.  相似文献   
98.
Narasin poisoning was reported in 15 camels, 7 adults and 8 young, after accidental access to poultry feed medicated with 60 g narasin per ton. Fourteen camels died between 3 and 20 days, and one young animal survived the dose after developing a chronic course of a disease. The main clinical signs of narasin toxicity in the dromedary include: weakness of hind limbs, lack of coordination, oedema of dependent parts, inappetence, ruminal atony, myoglobinuria, profound depression, tachycardia, sternal recumbency and death. The lesions were mainly in the heart and skeletal muscles and consisted of multifocal degeneration and necrosis of heart and skeletal muscle fibres with areas of regeneration and lung oedema. There was high enzyme activity for creatine kinase (CK), lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase and an increase in urea concentration and white blood cells, neutrophil and platelet counts. Cardiac markers, troponin T, CK-MB and C-reactive protein, showed slight or no changes terminally.  相似文献   
99.
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号